An exterior housing in an electronic device, such as mobile phone and smartphone is typically formed of a combination of a front exterior housing and a rear exterior housing each made of a synthetic resin, and to a surface of the front exterior housing a protection panel is fixed in order to protect a crystalline liquid display window. As the protection panel, a clear and colorless resin panel has been conventionally used. A recent trend is that a decoration, such as printed decoration rims, is introduced along with the emphasis of fashion aspect of the electronic devices.
In addition, recently, the protection panel as shown in FIG. 17 has been expected to have an input device function as a next interface of the mobile phone, and the technique is described, for example, in Patent Document 1.
The protection panel with a touch input function for protecting the electronic device display window will be further described in detail using the exploded view of FIG. 18. Referring to this drawing, a protection panel 1 with a touch input function includes: a lower electrode panel 3 having a non-flexible protection panel body, and on an upper face thereof, a lower transparent electrode 5 and lower circuits 7a,7b provided in a portion surrounding the lower transparent electrode 5; an upper electrode sheet 2a having a flexible transparent insulation film, and on a lower face thereof, an upper transparent electrode 4 provided at a position opposingly corresponding to a position of the lower transparent electrode 5, and upper circuits 6a-6d,7c,7d provided in a portion surrounding the upper transparent electrode 4; and a decorative sheet 2b having a flexible transparent insulation film and a decorative layer with a picture 17 for concealing the lower circuits 7a,7b and the upper circuits 6a-6d,7c,7d to form a transparent window 18.
The decorative sheet 2b is stuck together with an entire front face of the upper electrode sheet 2a (hereinafter, lamination of the upper electrode sheet 2a and the decorative sheet 2b is referred to as “movable sheet 2”). When a surface of the decorative sheet 2b is pressed with a finger, stylus or the like, the movable sheet 2 as a whole is bent downward, and as a result, the transparent electrodes 4,5 provided on the opposing faces of the upper electrode sheet 2a and lower electrode panel 3 are brought into contact, and thus an input position is detected.
FIG. 19 is a cross-sectional view showing one example of a mounting structure in the front exterior housing a protection panel with a touch input function. As shown in FIG. 19, in a front exterior housing 19, a panel fitting portion 22 is formed in such a manner that a protection panel 100 with a touch input function can be fitted thereinto. A depth of the panel fitting portion 22 is approximately the same as a thickness of the protection panel 100 with a touch input function, so that an outer face of the protection panel 100 is in the same plane as a portion of the front exterior housing 19 surrounding the outer face. In addition, in a bottom face of the panel fitting portion 22, there is provided an opening or recess 23 which is one size smaller than the bottom face, in such a manner that a display unit 20 is viewable from outside through a transparent window. The rim portion 22a of the bottom face supports a rim portion of the protection panel 100 with a touch input function on which the decorative layer is provided.